v0.7.13

Fixed

• No more lost request and BadHttpMethod error after the heater's
  GET /ping. This time the fix is based on a decrypted capture.
  • How the heater sends requests: each request's headers go in two
    TLS records. The second holds the last header and the blank line;
    for a GET that's Content-Length: 0, which completes the request.
  • The quirk: only /ping already ends its first record with a blank
    line, so the second record arrives after a complete request. The relay
    answered it 400 and closed the connection, and the heater retried 16
    seconds later.
  • Now: the relay drops that record only when it follows a complete
    request, and counts it in /state as stray_headers.
  • Why 0.7.10 failed: it dropped the record always, which cut the
    end off every normal request.